Cleanup: Make CheckClassId instruction more general so it

runtime/vm/intermediate_language_dbc.cc

Index: runtime/vm/intermediate_language_dbc.cc
diff --git a/runtime/vm/intermediate_language_dbc.cc b/runtime/vm/intermediate_language_dbc.cc
index 04dd1905c3b3188124993a2d46e095e4e6bc12fe..d7340743e04dd9c279400945f3bfc82549c336d4 100644
--- a/runtime/vm/intermediate_language_dbc.cc
+++ b/runtime/vm/intermediate_language_dbc.cc
@@ -252,7 +252,7 @@ EMIT_NATIVE_CODE(PolymorphicInstanceCall,
     }
     bool using_ranges = false;
     for (intptr_t i = 0; i < length; i++) {
-      if (targets_[i].cid_start != targets_[i].cid_end) {
+      if (!targets_[i].IsSingleCid()) {
         using_ranges = true;
         break;
       }
@@ -1490,7 +1490,14 @@ EMIT_NATIVE_CODE(CheckEitherNonSmi, 2) {
 
 
 EMIT_NATIVE_CODE(CheckClassId, 1) {
-  __ CheckClassId(locs()->in(0).reg(), compiler->ToEmbeddableCid(cid_, this));
+  if (cids_.IsSingleCid()) {
+    __ CheckClassId(locs()->in(0).reg(),
+                    compiler->ToEmbeddableCid(cids_.cid_start, this));
+  } else {
+    __ CheckClassIdRange(locs()->in(0).reg(),
+                         compiler->ToEmbeddableCid(cids_.cid_start, this),
+                         compiler->ToEmbeddableCid(cids_.cid_end, this));

[kustermann, 2017/05/18 09:59:45]

Please ASSERT that the range is within [0, 255] here.

Is it guaranteed by construction of the CheckClassId instruction?

[erikcorry, 2017/05/18 14:25:30]

Nice catch, this was wrong, fixed with a double DBC instruction.

+  }
   compiler->EmitDeopt(deopt_id(), ICData::kDeoptCheckClass);
 }
 
@@ -1523,7 +1530,7 @@ EMIT_NATIVE_CODE(CheckClass, 1) {
       int smi_adjustment = 0;
       int length = cids_.length();
       for (intptr_t i = 0; i < length; i++) {
-        if (cids_[i].cid_start != cids_[i].cid_end) {
+        if (!cids_[i].IsSingleCid()) {
           using_ranges = true;
         } else if (cids_[i].cid_start == kSmiCid) {
           ASSERT(cids_[i].cid_end == kSmiCid);  // We are in the else clause.